In order to achieve better channel utilization and increase overall performance, multiple transmission and multiple reception antennas (also commonly referred to as multiple input, multiple output (MIMO)) at both base station (BS) and mobile station (MS) are considered.
The knowledge of channel state information (CSI) is an important factor in wireless communication systems, particularly multi-user MIMO (MU-MIMO) systems. Codebook based quantization is a known method for feeding back the channel state information, as taught by Love, et al. (“What is the Value of Limited Feedback for MIMO Channels?” IEEE Communication Magazine, Vol. 42 pp 54-59. October 2004). As is also known, the precision of channel state information plays a key role in achieving the desired gains of Multi-user MIMO systems, per Jindal, (“MIMO Broadcast Channels with Finite Rate Feedback,” IEEE Trans. Information Theory, Vol. 52, No. 11, pp. 5045-5059, November 2006).
However, with MIMO systems, the size of the codebooks tends to grow dramatically with increased number of antennas and or codeword resolution. The increased codebook size increases storage requirements as well as increases codeword search times.
Therefore, there is a need for a system and method for providing CSI feedback without having large storage or computation requirements that increases dramatically with increased resolution or antennas. Furthermore, a need exists for a system and method for providing CSI feedback resolution with a flexible degree of resolution with simple quantization calculation that does not perform a complex, time consuming search.